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batman-adv: use vid when computing local and global TT CRC

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now that each TT entry is characterised by a VLAN ID, the
latter has to be taken into consideration when computing the
local/global table CRC as it would be theoretically possible
to have the same client in two different VLANs

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
This commit is contained in:
Antonio Quartulli 2013-06-04 12:11:40 +02:00 committed by Antonio Quartulli
parent c018ad3de6
commit 0ffa9e8d86
1 changed files with 31 additions and 4 deletions
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35
net/batman-adv/translation-table.c
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@ -1506,6 +1506,24 @@ struct batadv_orig_node *batadv_transtable_search(struct batadv_priv *bat_priv,
* batadv_tt_global_crc - calculates the checksum of the local table belonging
* to the given orig_node
* @bat_priv: the bat priv with all the soft interface information
* @orig_node: originator for which the CRC should be computed
*
* This function computes the checksum for the global table corresponding to a
* specific originator. In particular, the checksum is computed as follows: For
* each client connected to the originator the CRC32C of the MAC address and the
* VID is computed and then all the CRC32Cs of the various clients are xor'ed
* together.
*
* The idea behind is that CRC32C should be used as much as possible in order to
* produce a unique hash of the table, but since the order which is used to feed
* the CRC32C function affects the result and since every node in the network
* probably sorts the clients differently, the hash function cannot be directly
* computed over the entire table. Hence the CRC32C is used only on
* the single client entry, while all the results are then xor'ed together
* because the XOR operation can combine them all while trying to reduce the
* noise as much as possible.
*
* Returns the checksum of the global table of a given originator.
*/
static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node)
@ -1514,7 +1532,7 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv,
struct batadv_tt_common_entry *tt_common;
struct batadv_tt_global_entry *tt_global;
struct hlist_head *head;
uint32_t i, crc = 0;
uint32_t i, crc_tmp, crc = 0;
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
@ -1545,7 +1563,9 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv,
orig_node))
continue;
crc ^= crc32c(0, tt_common->addr, ETH_ALEN);
crc_tmp = crc32c(0, &tt_common->vid,
sizeof(tt_common->vid));
crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
}
rcu_read_unlock();
}
@ -1556,13 +1576,18 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv,
/**
* batadv_tt_local_crc - calculates the checksum of the local table
* @bat_priv: the bat priv with all the soft interface information
*
* For details about the computation, please refer to the documentation for
* batadv_tt_global_crc().
*
* Returns the checksum of the local table
*/
static uint32_t batadv_tt_local_crc(struct batadv_priv *bat_priv)
{
struct batadv_hashtable *hash = bat_priv->tt.local_hash;
struct batadv_tt_common_entry *tt_common;
struct hlist_head *head;
uint32_t i, crc = 0;
uint32_t i, crc_tmp, crc = 0;
for (i = 0; i < hash->size; i++) {
head = &hash->table[i];
@ -1575,7 +1600,9 @@ static uint32_t batadv_tt_local_crc(struct batadv_priv *bat_priv)
if (tt_common->flags & BATADV_TT_CLIENT_NEW)
continue;
crc ^= crc32c(0, tt_common->addr, ETH_ALEN);
crc_tmp = crc32c(0, &tt_common->vid,
sizeof(tt_common->vid));
crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
}
rcu_read_unlock();
}